Crystal Growth of Chalcogenides and Oxy-Chalcogenides Using Chloride Exchange Reaction

Chalcogenides and oxy-chalcogenides, including complex chalcogenides and transition metal dichalcogenides, are emerging semiconductors with direct or indirect band gaps within the visible spectrum. These materials are being explored for various photonic and electronic applications such as photodetectors, photovoltaics, and phase-change electronics. Understanding the fundamental properties of these materials is crucial for optimizing their functionalities. Therefore, the availability of large, high-quality single crystals of chalcogenides and oxy-chalcogenides is essential for a better comprehension of their structure and properties. In this study, we present a novel crystal growth method that utilizes the exchange reaction between BaS and ZrCl4/HfCl4. By carefully controlling the stoichiometric ratio of the binary sulfide to the chloride, we can grow single crystals of several materials, such as ZrS2, HfS2, BaZrS3, and ZrOS. This method results in large single crystals with a short reaction time of 24 to 48 h. High-resolution thin-film X-ray diffraction and single-crystal X-ray diffraction confirm the quality of the crystals produced through this exchange reaction. Importantly, we report optical properties, especially static and time-resolved photoluminescence, by studying their emission behavior and carrier dynamics to evaluate their suitability for optoelectronic applications. The chloride exchange reaction method paves the way for the synthesis of single crystals of chalcogenides and oxy-chalcogenide systems with a short reaction time but with low mosaicity and shall be an alternative single-crystal growth technique for materials that are challenging to grow, especially optical and optoelectronic materials.